Copper complexes of monosulfonamido formazyl dyes



Patented Dec. 8, 1953 7 2,662,075 7 corrnn coM'rLExEs F MONOSUL- FONAMIDO'FORMAZYL ores RebertA. Brooks, Salem, N. J., as'signor to if.

du .Pont de Nemours and Company, Wihning- Del, a corporation of Delaware N 0 Drawin Application June; 1;952:, i Serial No. $1,970

roman, (01. 260 449) This invention relates to novel organic compounds useful as dyestufisfor certain tentile fibers, especially nylon and wool. V

invention iswbased on the discovery that the copper complexes of certain novel, iormazyl dyes as more fully defined below possessthe rare property of dyeing nylon, and other hydrophobic fibers in bright, deep blue shades from a neutral bath. From the praetical viewpoint; this is an important discovery, because dyes capable of dyeing nylon from a neutralbath have been lacking in the blue region of the spectrum.

The novel formazyl dyes referred to above may be representedby the general formula coon S OaNH:

wherein the X's represent hydrogen, chloro or nitro groups, but wherein the dye molecule is otherwise unsubstituted. It will be noted that the dyemoleculeposse'sses an OH, COOH pair iniopposite rings but eachsituated ortho to an N-ato'm, and that the benzoic acid rin'gbears a sulfonamido radieal inposition para to an N-atom. It will be noted further that tautomeric rearrangement may interchange the positions of the azo and hydrazo linkages.

These novel formazyl dyes may be synthesized by diazotizing an ortho amino-phenol and coupling the diazo compound, under alkaline conditions, to an aryl-hydrazone compound obtained by condensing'the hydrazine of 2-amino-5-sulfonamido-benzoic acid with benzaldehyde. The azo-hydrazone compound thus obtained is then copperized in known manner, for instance by reacting the same in an ammoniacal aqueous solution with a. copper salt. Recovery of the copperized dye may then be effected simply by filtration and washing.

An alternative method available is to diazotize 2-amino-5-sulfonamido-benzoic acid and couple the diazo compound to the aryl hydrazone obtained by condensing the corresponding orthohydroxy-phenyl-hydrazine with benzaldehyde. This method applies only to the case of chloroor nitro-substituted o-hydroXy-phenyl-hydrazines, which by virtue of the named negative substituents may be prepared on a practical scale from the corresponding o-aminophenols. Copperization may then be effected in the manner indicated above. 7

'Without' limiting my invention, the following examples ar ev n t l u t at my pr r e mode of operation; Parts mentioned are by weight. 7

(a Preparation; of azoehfldmzon'c compound A ur Q 5- .5 par f i i9=4?=ni? ophh0 parts or w r cent-a fling 1;.sz pgrtso hyaro'cmqu a hea di o, 6 c. an filtered. The filtrat wasic edf to 2 (J1 11112.07 p r s of s d umbitri 'i he' o' iq i a q e u solution was added slowly, as taken; up. In a e a vess l; 2 one drb hz m iy ca 'csarboxyg-sdliamylT-jih riy hydrazonewere disfs'olved in pa of w er'c'o aining' 4) parts or sodium hydrox de; 'rneselutmn was icedto +256. and thediazb solution was" added to it "while maintaining-good agitatidria Alter further stirring for one hour; the} deflection mass was acidified with acetic acid, and the" precipitated azo-hydra'zone dye -base" was" filtered o'iif and washed. I x

(b) lreparction-ofithe cbm f c' iiiplex' A clear, darlc' solutioii was"produced-by dissolv 1322' parts' of theicrudcolor base; above, in 45' parts: (if-28% ammonia? Similarly, :6 parts of 'copp er acetate' weredissolved in 5 0; parts, of water andsfi outset-2+8 %:=a menia W tb a idasita: tion,- these s lutions: we a, andwee tlv warmed. The copper complex was precipitated, isolated by filtration and washed with water. After drying at 75 0., the essentially pure metallized product was obtained. It was a bright-blue powder, insoluble in water but readily soluble in dimethyl-formamide. It dyed nylon from a neutral bath in attractive blue shades with good light fastness but only moderate wash fastness.

In a manner similar to the above example, the copper complexes of the following formazyl dye bases were prepared:

Example Diazo component from- 2-amino-4, 6dinitrophenol. 2-amino-4-chlorophenol. 2-aminophenol.

(2 hydroxy 5 nitro) phenyl-hydrazone were added to a solution'of l parts of sodium hydroxide in 150 parts of water. obtained was iced to 0 C.

The diazo slurry was added quickly to the hydrazone solution with rapid agitation. Cou- The clear solution thus designed for use on nylon fiber.

pling began at once but 2 hours of agitation at 510 C. were required before a negative test for diazo was obtained with resorcinol. Glacial acetic acid was thenadded dropwise until a pH of approximately 8 was obtained. The mixture was warmed to room temperature and filtered. After drying at 75 C., the azo-hydrazone compound was obtained in a state of high purity.

The copper complex was then prepared as described in Example 1. It was found to produce blue dyeings, of good fastness to light and fair to good fastness to washing, when applied to nylon or wool from a neutral dye bath.

It will be understood that the details of the above examples may be varied widely without departing from the spirit of the invention. Thus, the operations of diazotizing, coupling, preparing the hydrazines and condensing the latter with benzaldehyde, are per se well known, and may be varied within the skill of those engaged in this art. The only precaution to be observed is to avoid subjecting the color bases (that is, prior to copperization) to prolonged contact with strong alkali except at temperatures near or below 0 C.

For copperization, any water-soluble salt of copper may 'beused, for instance. the acetate, sulfate, chloride or nitrate. The use of ammonia enables metallization to be achieved at room temperature, but is otherwise not essential.

The practical advantages of my invention will now be readily apparent. The copper complexes of this application are capable of producing 4 bright, blue shades, of good fastness to light and moderate to good fastness to washing, on nylon and wool. They may also be used on other hydrophobic fibers, for instance polyacrylonitrile.

Analogous compounds-which contain free sulfonic acid groups instead of sulfonamide groups dye these fibers from an acid bath only. The compounds of this invention have the advantage of dyeing from a neutral bath, and may be used in combination with other neutral dyeing colors, Such neutral dyeing colors have the advantages over the acid colors of producing levelness in dyeing (particularly on nylon), of producing heavy shades on nylon and of not having a tendering eflect on wool. Prior to my discovery of the dyestuffs of this application, a bright blue for the said neutral-dyeing line was entirely lacking.

The dyestuffs of this invention may be prepared for dyeing in the same manner as the other neutral-dyeing dyes above mentioned, that is by an aqueous milling treatment preferably in the presence of a dispersing agent such as a lignin sodium sulfonate. The dyes so milled are applied to the nylon or wool fibers from a neutral aqueous bath at about -100 C.

I claim as my invention:

The copper derivatives of formazyl dyes having the general formula S OaNHa V I ROBERT A. BROOKS.

References Cited in the file of this patent Saunders: Aromatic Diazo Compounds, 1949, pages 214-5. 

